Medial temporal lobe stimulation may disrupt context-dependent memory retrieval

Multiple trace theory (MTT) predicts that hippocampal memory traces expand and strengthen as a function of repeated memory retrievals. We tested this hypothesis utilizing fMRI, comparing the effect of memory retrieval versus the mere passage of time on hippocampal activation. While undergoing fMRI scanning, participants retrieved remote autobiographical memories that had been previously retrieved either one month earlier, two days earlier, or multiple times during the preceding month. Behavioral analyses revealed that the number and consistency of memory details retrieved increased with multiple retrievals but not with the passage of time. While all three retrieval conditions activated a similar set of brain regions normally associated with autobiographical memory retrieval including medial temporal lobe structures, hippocampal activation did not change as a function of either multiple retrievals or the passage of time. However, activation in other brain regions, including the precuneus, lateral prefrontal cortex, parietal cortex, lateral temporal lobe, and perirhinal cortex increased after multiple retrievals, but was not influenced by the passage of time. These results have important implications for existing theories of long-term memory consolidation.

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Working memory retrieval differences between medial temporal lobe epilepsy patients and controls: A three memory layer approach

Brain and Cognition ◽

10.1016/j.bandc.2013.11.004 ◽

2014 ◽

Vol 84 (1) ◽

pp. 90-96 ◽

Cited By ~ 2

Author(s):

José María López-Frutos ◽

Claudia Poch ◽

Irene García-Morales ◽

José María Ruiz-Vargas ◽

Pablo Campo

Keyword(s):

Working Memory ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Memory Retrieval ◽

Medial Temporal Lobe ◽

Medial Temporal Lobe Epilepsy

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Decision letter: Delay-dependent contributions of medial temporal lobe regions to episodic memory retrieval

10.7554/elife.05025.022 ◽

2014 ◽

Keyword(s):

Episodic Memory ◽

Temporal Lobe ◽

Memory Retrieval ◽

Medial Temporal Lobe ◽

Delay Dependent

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Delayed Verbal Memory Retrieval: A Functional MRI Study in Epileptic Patients with Structural Lesions of the Left Medial Temporal Lobe

NeuroImage ◽

10.1006/nimg.2001.0908 ◽

2001 ◽

Vol 14 (5) ◽

pp. 995-1003 ◽

Cited By ~ 37

Author(s):

Sophie Dupont ◽

Yves Samson ◽

Pierre-François Van de Moortele ◽

Séverine Samson ◽

Jean-Baptiste Poline ◽

...

Keyword(s):

Functional Mri ◽

Temporal Lobe ◽

Verbal Memory ◽

Memory Retrieval ◽

Medial Temporal Lobe ◽

Epileptic Patients ◽

Mri Study

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Coupled ripple oscillations between the medial temporal lobe and neocortex retrieve human memory

Science ◽

10.1126/science.aau8956 ◽

2019 ◽

Vol 363 (6430) ◽

pp. 975-978 ◽

Cited By ~ 53

Author(s):

Alex P. Vaz ◽

Sara K. Inati ◽

Nicolas Brunel ◽

Kareem A. Zaghloul

Keyword(s):

Human Brain ◽

Temporal Lobe ◽

Verbal Memory ◽

Memory Retrieval ◽

Medial Temporal Lobe ◽

Direct Evidence ◽

Human Memory ◽

Association Cortex ◽

Temporal Association ◽

Neural Representations

Episodic memory retrieval relies on the recovery of neural representations of waking experience. This process is thought to involve a communication dynamic between the medial temporal lobe memory system and the neocortex. How this occurs is largely unknown, however, especially as it pertains to awake human memory retrieval. Using intracranial electroencephalographic recordings, we found that ripple oscillations were dynamically coupled between the human medial temporal lobe (MTL) and temporal association cortex. Coupled ripples were more pronounced during successful verbal memory retrieval and recover the cortical neural representations of remembered items. Together, these data provide direct evidence that coupled ripples between the MTL and association cortex may underlie successful memory retrieval in the human brain.

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The Potentiation of Associative Memory by Emotions: An Event-Related FMRI Study

Advances in Neuroscience ◽

10.1155/2014/964024 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 9

Author(s):

David Luck ◽

Marie-Eve Leclerc ◽

Martin Lepage

Keyword(s):

Performance Improvement ◽

Entorhinal Cortex ◽

Associative Memory ◽

Temporal Lobe ◽

Memory Retrieval ◽

Medial Temporal Lobe ◽

Emotional Valence ◽

Neural Correlates ◽

Fmri Study ◽

The Right

Establishing associations between pieces of information is related to the medial temporal lobe (MTL). However, it remains unclear how emotions affect memory for associations and, consequently, MTL activity. Thus, this event-related fMRI study attempted to identify neural correlates of the influence of positive and negative emotions on associative memory. Twenty-five participants were instructed to memorize 90 pairs of standardized pictures during a scanned encoding phase. Each pair was composed of a scene and an unrelated object. Trials were neutral, positive, or negative as a function of the emotional valence of the scene. At the behavioral level, participants exhibited better memory retrieval for both emotional conditions relative to neutral trials. Within the right MTL, a functional dissociation was observed, with entorhinal activation elicited by emotional associations, posterior parahippocampal activation elicited by neutral associations, and hippocampal activation elicited by both emotional and neutral associations. In addition, emotional associations induced greater activation than neutral trials in the right amygdala. This fMRI study shows that emotions are associated with the performance improvement of associative memory, by enhancing activity in the right amygdala and the right entorhinal cortex. It also provides evidence for a rostrocaudal specialization within the MTL regarding the emotional valence of associations.

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